so sánh 2020.2021-1/2020.2021 và 2021.2022-1/2021.2022
2 câu trả lời
`(2020 . 2021 - 1)/(2020 . 2021) = (2020.2021)/(2020 . 2021) - 1/(2020 . 2021) = 1 - 1/(2020 . 2021)`
`(2021.2022 - 1)/(2021.2022) = (2021.2022)/(2021.2022) - 1/(2021.2022) = 1 - 1/(2021.2022)`
Có:
`1/(2020 . 2021) > 1/(2021.2022)`
`=> 1 - 1/(2020 . 2021) < 1 - 1/(2021.2022)`
`=> (2020 . 2021 - 1)/(2020 . 2021) < (2021.2022 - 1)/(2021.2022)`
Vậy `(2020 . 2021 - 1)/(2020 . 2021) < (2021.2022 - 1)/(2021.2022)`
Đáp án
2020.2021-1/2020.2021= 2021-1/2020=2020.999505
2021.2022-1/2021.2022=2022-1/2021=2021.999505
vì 2020.999505<2021.999505
=> 2020.2021-1/2020.2021 < 2021.2022-1/2021.2022
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